Iontophoresis

Question 1

What is it?

Answer 1

Transdermal drug delivery using low voltage direct current to move ions across a dermal barrier

Question 2

does iontophoresis “drive” ions through the skin?

Answer 2

more recent literature points to the fact it more likely increases permeability of corneum stratum

Question 3

Depth of penetration

Answer 3

• 3-20 mm
• may be linked to molecular structure being moved

Question 4

why is medication placed in aqueous solution?

Answer 4

• To dissociate into + and - ions
• Low volt direct current can then use polarity to move these ions
• So you need to know if medicine is + or -

Question 5

Mechanisms of ion transfer

Answer 5

• electromigration
• electroporation
• electroosmosis

Question 6

Electroporation

Answer 6

• Increase in porosity of epidermis in response to e-stim
• skin is hydrophobic
• after e-stim, there is a temporary increase in skin porosity

Question 7

Electromigration

Answer 7

• movement of ions into tissue
• based on “volume flow” and not just diffusion

Question 8

Electroosmosis

Answer 8

• human skin has a net (-) charge
• Ions moving from + to -
  So, for + charged ions, this may enhance the delivery of ions as they are “going with the flow” and hinder movement of (-) ions

Question 9

What is the driving force behind iontophoresis?

Answer 9

repulsion of like charges

Question 10

what polarity do i use?

Answer 10

• positively charged ions will be repelled by the positive pole (anode)
• negatively charged ions will be repelled by the negative pole (cathode)

Question 11

Dosage

Answer 11

• 20 mA mins to 160 mA mins
• 40 mA mins and 80 mA mins most common
• this information given by the prescriber

Question 12

intensity

Answer 12

To tolerance
Most units do not exceed 4 mA

Question 13

what drives the time of the treatment?

Answer 13

intensity (mA)

Question 14

Skin reaction - cathode

Answer 14

• sodium hydroxide can form under the cathode
• caustic
• known as an “alkaline reaction”

Question 15

skin reaction - anode

Answer 15

• hydrocholoric acid can form under the anode
• known as an “acidic reaction”
• slightly more comfortable than the alkaline reaction

Question 16

Current density should not exceed:

Answer 16

0.5 mA/cm2 for the cathode (-)
1.0 mA/cm2 for the anode (+)
** Not usually a problem with commercial units

Question 17

what type of set up should you always use?

Answer 17

monopolar

Question 18

electrode placement - active

Answer 18

+ or - based on the medication type
smaller electrode
place directly over treatment area

Question 19

electrode placement - dispersive

Answer 19

opposite of active
larger electrode
place at a distance from active (usually proximal)

Question 20

Acetic Acid (acetate)

Answer 20

(-)
purpose: calcium deposits

Question 21

Dexamethasone

Answer 21

(-)
purpose: inflammation

Question 22

Iodine

Answer 22

(-)
purpose: scars

Question 23

Lidocaine

Answer 23

(+)
purpose: anesthetic

Question 24

Precautions and Contraindications

Answer 24

• stimulation across chest
• pacemaker
• over carotid sinuses
• uncontrolled hypertension
• PVD
• thrombophlebitis
• pregnancy
• impaired sensation
• confused patients
• uncontrolled seizures
• obesity
• cancer

Question 25

Treatment Procedure first things first

Answer 25

• select appropriate medication for the condition
• inspect skin for cuts, abrasion, scars, etc
• check sensation
• check for other contraindications/ precautions
• instruct patient about the treatment (why, how, what to expect)

Question 26

Treatment procedure - set up

Answer 26

• position pt for comfort
• clean and prep skin
• prepare active electrode by placing meds on pad with syringe
• place active electrode over treatment area
• place dispersive electrode at a distance from active
• connect lead wires
• turn on device
• set dosage
• allow ramp of intensity if indicated by unit
• turn up intensity based on tolerance
• terminate and remove electrodes

Question 27

after the treatment

Answer 27

• remove electrodes
• inspect skin